Method for operating a heat generator

Abstract

The invention relates to a method for operating a heat generator (1, 12), comprising: defining a target heat amount Qsoll in a hydraulic circuit; detecting a first actual temperature T1 of a heating circuit medium in the circuit; detecting a second actual temperature T2 at a second point in time t2; determining a rise in temperature ΔT as the difference between the second actual temperature T2 and the first actual temperature T1; detecting a heat amount Qzu introduced into the hydraulic circuit; determining a target temperature Tsoll of the heating circuit medium on the basis of the target heat amount Qsoll, the rise in temperature ΔT and the introduced heat amount Qzu; and operating the heat generator (1, 12) on the basis of the determined target temperature Tsoll.

Description

[0001] Method for operating a heat generator

[0002] The present invention relates to a method for operating a heat generator. In particular, the thermal mass of a hydraulic circuit is to be determined in order to provide the amount of heat required for defrosting a heat pump.

[0003] Modern heat pumps are characterized by their high efficiency, making them particularly attractive for heating and / or cooling a building from both an ecological and economic perspective. Heating with ambient heat is, on the one hand, climate-friendly. On the other hand, many energy suppliers have been offering special heat pump tariffs for several years that are more financially attractive than a standard electricity tariff.

[0004] A typical heat pump has a circuit for a refrigerant. The refrigerant absorbs heat from the environment at an evaporator. Favored by low outside temperatures of approximately 7 to 10°C and below, a layer of frost and / or ice can form on the heat pump's evaporator, which can impede heat transfer at the evaporator and thus impair the heat pump's efficiency. The ice layer then usually needs to be removed through a defrosting process.

[0005] The German patent application DE 10 2018 102 670 A1 describes a heat pump 1 with an integrated buffer storage tank 3, which is shown schematically in Fig. 1. The heat pump system 10 shown in Fig. 1 consists, in a known manner, initially of a heat pump 1 and a heat sink 2. As heat sink 2, a heating circuit 2.1 with a plurality of radiators 2.3 and a hot water tank 2.2 are shown as an example in Fig. 1. In a first operating mode, referred to as normal operation or heating mode, ambient heat is transferred from the heat pump 1 to the heat sink 2. In addition, the buffer storage tank 3 can be charged with heat in a second operating mode, referred to as buffer charging mode. The buffer storage tank 3 stores heat for defrosting the heat pump 1 and is therefore also referred to as a defrost buffer. In a third operating mode, known as defrosting mode, heat is transferred from the buffer storage tank 3 to the heat pump 1 for defrosting.The refrigerant circuit of heat pump 1 is operated in reverse mode.

[0006] The heat pump system 10 has a heat exchanger 6 operating as a condenser and through which a heating circuit medium flows. An outlet 3.2 of the buffer tank 3 is connected upstream of an inlet 6.2 of the heat exchanger 6, as seen in the flow direction of the heating circuit medium. The heating circuit medium flows via a return line RL from the heat sink 2 or from the outlet 3.2 of the buffer tank 3 towards the heat pump 1, which is indicated in Fig. 1 by an arrow pointing to the left. Correspondingly, the heating circuit medium flows via a flow line VL from the heat pump to the heat sink 2 or to the inlet 3.1 of the buffer tank 3, which is indicated in Fig. 1 by an arrow pointing to the right.

[0007] The heat pump system 10 shown in Fig. 1 consists of two interconnected system components, one of which is located inside the building and one outside the building. Such a configuration is also referred to as a split heat pump. The two system components are usually referred to as the outdoor unit (ODU) and the indoor unit (IDU). The coolant circulates between the outdoor unit ODU and the indoor unit IDU. In this embodiment, the buffer storage tank 3 is also arranged in the indoor unit IDU. A heating circuit pump 7 for circulating the heating circuit medium is arranged between the inlet 6.2 of the heat exchanger 6 at the return flow RL and the buffer storage tank s. Furthermore, a temperature sensor 11 for measuring the return flow temperature of the heating circuit medium is arranged in the return flow RL.

[0008] During normal operation and in buffer charging mode, the refrigerant of heat pump 1 absorbs ambient heat at a comparatively low temperature level via the outdoor unit ODU (Fig. 1 schematically shows the evaporator 5 with fan 8). The refrigerant is then transported via a compressor 9.1 to the heat exchanger 6, which acts as a condenser, where it transfers the heat to the heating circuit medium. The refrigerant is then expanded in a known manner via an expansion valve 9.2 before returning to the evaporator 5.

[0009] From heat exchanger 6, the heating circuit medium first flows via the flow line VL to a valve 4, which may be designed as a 4 / 3-way valve, for example. Depending on requirements, the heating circuit medium is then directed to heating circuit 2.1 with radiators 2.3 and / or to the hot water tank 2.2. The cooled heating circuit medium returns to heat exchanger 6 via the return line RL through inlet 6.2 to close the circuit.

[0010] Since the evaporator of the outdoor unit (ODU) of such a heat pump system 10 tends to ice up under certain weather conditions, it is occasionally necessary to defrost it. This is done by reversing the heat pump cycle, i.e., evaporator 5 is now operated as a condenser and heat exchanger 6 as an evaporator.

[0011] The heat required for the defrosting process is not extracted from the heat sink 2, but is provided by the dedicated buffer storage 3. The heat for the defrosting process can be supplied to the buffer storage 3 during normal operation or, alternatively, only during buffer charging. During defrosting, the buffer storage 3 serves as a heat source for defrosting the evaporator 5, which then functions as a condenser.

[0012] In the described embodiment of the heat pump 1 with an outdoor unit ODU and an indoor unit IDU, the buffer storage tank 3 can be arranged very close to the heat exchanger 6, so that the amount of heat reserved for the defrosting process depends mainly on the volume of the buffer storage tank 3. In a monoblock heat pump, however, the buffer storage tank 3 can be arranged comparatively far away from the heat exchanger 6, so that the volume of the lines between the buffer storage tank 3 and the heat exchanger 6 as well as the heat capacity of the lines themselves and of installed components such as sensors, valves and the like, which are in thermal exchange with the heating circuit medium, are not negligible.

[0013] The present invention is therefore based on the object of overcoming the problems known in the prior art and of providing a method for operating a heat generator that is improved compared to the prior art. Furthermore, a heating system that is improved compared to the prior art is to be provided.

[0014] The object is achieved according to the invention by a method for operating a heat generator according to claim 1 and by a heating system according to claim 9. Preferred embodiments of the present invention are the subject of the dependent claims, the attached drawings and the following description of exemplary embodiments.

[0015] A heating system according to the invention comprises a heat generator or a plurality of heat generators. A preferred embodiment of the heating system comprises a heat pump as the heat generator, whereby the heat pump can also simultaneously serve as the load. In particular, the refrigerant circuit of the heat pump can be considered a load. The term "load" generally refers to a heat sink. In the example of the heat pump as a load, it absorbs heat during a defrosting process and can thus be operated as a load or heat sink.

[0016] In addition to the heat pump, the heating system can have at least one additional heat generator. Examples of additional heat generators include a gas condensing boiler, an oil boiler, a combined heat and power plant, a fuel cell, a solar thermal system, or other devices that can provide heat to the heating circuit medium. The additional heat generator can also be referred to as an external heat generator, as it is not part of the heat pump.

[0017] Furthermore, the heat pump can have an electric heat generator, such as a heating element, as an auxiliary heat generator, for example, in the event that the heat pump cannot generate sufficient heat at low outside temperatures. A heat pump with an additional electric heating element is described, for example, in DE 699 25389 T2. If the outside temperature is below a certain threshold, the additional electric heating element is activated to heat the heat pump's supply air. In alternative embodiments, the auxiliary heat generator can directly heat the heating circuit medium and / or the refrigerant.

[0018] A heating system according to the invention is preferably used to heat a building. The heating system can have a heating circuit with a plurality of radiators and / or an underfloor heating system and / or a heat storage unit as a heat sink.

[0019] The method steps described below can preferably be carried out by a control device of the heating system, which in particular regulates and / or controls the heat generator and / or other components of the heating system, for example, one or more valves. Functions of the control device can be carried out entirely or partially by a geographically remote device, for example, a cloud or a server. For this purpose, a local control device of the heating system can be connected to a network, for example, the Internet, via a suitable interface.

[0020] The at least one heat generator heats the fluid heating circuit medium, which circulates in a hydraulic circuit. Water, in particular, can be used as the heating circuit medium. The hydraulic circuit comprises lines for the heating circuit medium and connects a load, a buffer tank, and the heat generator. The heating circuit medium can preferably also be supplied to the heating circuit via a valve.

[0021] Hydraulic lines that belong to the heat sink of the heating system are preferably not part of the hydraulic circuit under consideration. The heating circuit medium in the hydraulic circuit, as well as the associated lines and thermal losses, etc., form a total thermal mass of the hydraulic circuit. Using this method, this total thermal mass of the circuit can be determined, allowing a specified target heat quantity Q S0 H can be introduced into the hydraulic circuit as efficiently as possible.

[0022] The target heat quantity Q S0 According to a preferred embodiment, n can be used in particular to remove frost or ice from an evaporator of a heat pump during a defrosting process. The target heat quantity Q S0 H can depend in particular on the type and size of the load of the heat pump, as well as on the outside temperature.

[0023] To determine the total thermal mass of the hydraulic circuit, a temperature lift AT is first determined as the difference between a first actual temperature TI of the heating circuit medium at a first time t1 and a second actual temperature T2 of the heating circuit medium at a second time t2, which is a predetermined period of time t1 after the first time t1. The temperature lift AT is thus derived from the following equation:

[0024] AT = T2 - Tl (1)

[0025] Furthermore, the amount of heat Q introduced into the hydraulic circuit by the heat generator during the period At zu This can be done, for example, by integrating the applied heat output over the period Δt. It should be noted that more than one heat generator can be used to introduce heat into the hydraulic circuit. In this case, the sum of the integrated heat outputs is referred to below as the introduced heat quantity Q zu used.

[0026] The desired total thermal mass of the hydraulic circuit is the quotient of the heat quantity Q introduced zu and the temperature stroke AT:

[0027] (m ■ c)dead = Q Z u / AT (2)

[0028] Here, m denotes the total mass of the hydraulic circuit, including the heating circuit medium, pipes, and fittings. Furthermore, c denotes the total heat capacity. The product (m ■ c)tot denotes the total thermal mass of the hydraulic circuit.

[0029] In order for the introduced heat quantity Q zu If the procedure only applies to the hydraulic circuit, a heating circuit is disconnected from the heating circuit fluid supply before the procedure is carried out. A controllable valve can be installed in the heating system for this purpose.

[0030] In the heat pump system according to the prior art described above, which is shown in Fig. 1, pipes, containers, and the like can be neglected when calculating the total thermal mass, since essentially only the volume of the buffer tank 3 is decisive here. However, with comparatively long pipes between the buffer tank s and the heat exchanger 6, the volume of the heating circuit medium contained therein as well as the heat capacity of the pipes themselves must also be taken into account. Since it is particularly difficult to analytically determine the contribution of pipes, fittings, and the like, the temperature difference AT can be determined by determining the temperature difference AT and comparing it with the introduced heat quantity Q zuA relatively accurate measurement of the total thermal mass can be performed without precise knowledge of the system configuration. Using the method described here, the total thermal mass of the entire circuit under consideration can be determined by measuring the temperature of the heating circuit medium.

[0031] With the values ​​determined above, a target temperature T can be calculated using the following equation so n of the heating circuit medium depending on the target heat quantity Qsoii can be calculated:

[0032] Tsoll — Qset / (m ■ C)tot + Tmin (3)

[0033] Here, Tmin represents a specified minimum temperature of the heating circuit medium.

[0034] The minimum temperature T m in can be specified depending on the operating mode. For example, the minimum temperature T min heating mode should be approximately 5°C. For defrosting mode, an increased minimum temperature Tmin of, for example, approximately 35°C can be specified. The minimum temperature Tmin for defrosting mode can, in particular, ensure that the heat exchanger operating as an evaporator in defrosting mode does not freeze. In equation (3), the minimum temperature Tmin also serves as the zero level for determining the setpoint temperature T so ii of the heating circuit medium. If the amount of heat required for defrosting is determined with sufficient accuracy and then released during defrosting, in the most energy-efficient case, the minimum temperature Tmin can be reached exactly at zero after defrosting. The minimum temperature Tmin can, in particular, be a preset value provided by the heat pump.

[0035] According to the procedure, the heat generator is controlled depending on the determined target temperature T S0n. This can mean, for example, that the heat generator is operated at maximum heating output until the actual temperature of the heating circuit medium is equal to or greater than the set temperature T S0 n is.

[0036] The actual temperature of the heating circuit medium is preferably measured between the buffer tank and the load. In other words, the temperature sensor is preferably located between the buffer tank and the load, i.e., in the return flow. With such an arrangement, the measured temperature is also referred to as the return flow temperature.

[0037] According to a preferred embodiment, the load is a refrigerant circuit of a heat pump. This corresponds to the case described above according to the prior art in Fig. 1, wherein the heat pump's heat exchanger functions as an evaporator in reverse operation. The heat flows from the buffer tank via the return line to the heat pump. The heat from the heating circuit medium is transferred to the refrigerant via the condenser of the refrigerant circuit, which operates as an evaporator, and can then heat the evaporator of the heat pump, which operates as a condenser during defrosting, so that any ice or frost formed on it is thawed.

[0038] In a preferred defrosting process, the buffer storage is loaded until the current actual temperature of the heating circuit medium is equal to or greater than the setpoint temperature T S0n. Since the actual temperature is preferably measured downstream of the buffer tank, i.e., in the return line, the measured actual temperature can be used to determine the storage temperature of the buffer tank. In preferred embodiments, at least one additional temperature sensor can be arranged in the buffer tank to measure the storage temperature.

[0039] A specified charge level of the buffer storage can be reached, for example, when the buffer storage or the heating circuit medium at the temperature sensor reaches the target temperature T S0 n has been reached.

[0040] As soon as the target temperature T S0 n in the heating circuit medium is reached, the circuit has the specified target heat quantity Q S0 H. Accordingly, a defrosting process can then be carried out to defrost the heat pump's evaporator.

[0041] The specified target heat quantity Q S0n can preferably be determined depending on the outside temperature and the type of heat pump. The outside temperature can, for example, be measured by an outside temperature sensor or received from the heating system's control unit.

[0042] According to a preferred embodiment, the heat generator is operated with maximum heating output when loading the buffer storage tank until the actual temperature of the heating circuit medium is equal to or greater than the target temperature T S0 H. In this case, a heating power can preferably be determined in advance which is required to reach the target temperature T S0 n to be achieved. If the required heating output is greater than the maximum heating output of the heat generator, a second heat generator can be operated to heat the heating circuit medium.

[0043] The control device can preferably have an interface. The interface of the control device for outputting messages to a user or operator of the heating system can generally be understood as a human-machine interface (HMI), via which the user or operator can preferably also make inputs. In a preferred embodiment, the HMI can be an application (“app”) on the user’s or operator’s mobile device. The cloud or the server can also be used as an interface. In particular, access to data in the cloud or on the server can be enabled via an internet browser, which can also enable control-related interventions.

[0044] Preferably, the heat pump can be operated in a first operating state as a heat generator for heating the building. The first operating state corresponds to normal operation or heating operation of the heat pump. Preferably, a user or operator can switch the heat pump to the first operating state via the interface. Further preferably, the heat pump can be operated in a second operating state for defrosting the heat pump. The methods described here are carried out in particular when the heat pump is operated in the second operating state for defrosting the heat pump.

[0045] BRIEF DESCRIPTION OF THE CHARACTERS

[0046] Further advantageous embodiments are described in more detail below with reference to an embodiment shown in the drawings, to which the invention is not limited, however.

[0047] They show schematically:

[0048] Figure 1 illustrates a generic heat pump system.

[0049] Figure 2 illustrates a heat pump system according to a first

[0050] Embodiment of the present invention.

[0051] Figure 3 illustrates a heat pump system according to a second

[0052] Embodiment of the present invention. Figure 4 shows a diagram describing the dependence of defrost energy on the outside temperature.

[0053] DETAILED DESCRIPTION OF THE INVENTION USING EXEMPLARY EMBODIMENTS

[0054] In the following description of a preferred embodiment of the present invention, like reference numerals designate like or comparable components.

[0055] Fig. 2 illustrates an embodiment of a heating system 10 according to the invention for a building. The heating system 10 according to the invention is constructed similarly to the known heat pump system 10 of Fig. 1. The same reference numerals designate the same or similar components.

[0056] The heating system 10 of Fig. 2 comprises a heat pump 1, which is designed as a monoblock heat pump. The individual components of the heat pump 1, such as the evaporator 5, the refrigerant circuit, and the heat exchanger 6, are arranged in the outdoor unit ODU of the heat pump 1 and are not shown in Fig. 2.

[0057] In contrast to heat pump 1 in Fig. 1, in which the heat exchanger 6 is located in the indoor unit IDU, this component is located in the outdoor unit ODU in heat pump 1 in Fig. 2. Otherwise, the structure of the heating system 10 in Fig. 2 is essentially identical to Fig. 1.

[0058] The heating system 10 can be operated in one of three modes. A first mode is normal operation or heating mode, in which the heat pump 1 provides heat for the heat sink 2. A second mode is buffer charging mode, in which the heat pump 1 provides heat for charging the buffer storage tank 3. A third mode is defrosting mode, in which the heat pump 1 is operated in reverse for defrosting and absorbs the heat stored in the buffer storage tank 3.

[0059] According to a preferred embodiment, the buffer storage tank 3 can also be charged in parallel with heating operation. This can also be considered a fourth operating mode, in which the heat pump 1 is preferably operated at maximum heating output.

[0060] The length of the supply line VL and the return line RL between buffer tank 3 and heat pump 1 can be approximately 2 meters to 25 meters, preferably approximately 6 meters to 20 meters, for typical outdoor monoblock heat pump installations. Please note that the length of the lines in Fig. 2 is not drawn to scale.

[0061] The capacity of the buffer tank 3, which preferably serves exclusively to store heat for the defrosting process, is approximately 10 liters to approximately 20 liters. Due to the total length of the lines between buffer 3 and heat exchanger 6 of the heat pump 1 of approximately 4 meters to approximately 50 meters, preferably approximately 12 meters to approximately 40 meters, the thermal mass of the heating circuit medium in the lines, as well as the thermal mass of the lines and the internal components themselves, cannot be neglected compared to the volume of the buffer 3. Furthermore, the total thermal mass of the hydraulic circuit can also include heat losses that cannot be precisely quantified a priori.

[0062] In order to carry out a defrosting process of the heat pump 1 as efficiently as possible, it is advantageous to set the required target heat quantity Q S0H as accurately as possible. In addition, it is desirable to adjust the heat quantity introduced into the hydraulic circuit as accurately as possible to the target heat quantity Q S0 H. If the heating system 10 is operated in an operating state for defrosting the heat pump 1, the hydraulic circuit including buffer tank 3 is first supplied with the required target heat quantity Q S0 H. To do this, in a first step, the heat sink 2 with the heating circuit 2.1 and the hot water tank 2.2 can be separated from the hydraulic circuit via the valve 4.

[0063] In a next step, a first return temperature TI of the heating circuit medium is recorded at a first time t1. After a predetermined time period Δt, a second return temperature T2 of the heating circuit medium is recorded at a second time t2. The predetermined time period Δt can be, for example, 60 to 600 seconds, preferably 60 to 180 seconds. More preferably, the predetermined time period Δt is approximately 120 seconds.

[0064] To measure the return temperatures, a return temperature sensor 11 is arranged in the return line RL between buffer tank 3 and heat pump 1. Additionally, further temperature sensors can be arranged in the heating system 10 (not shown), for example in buffer tank 3 and / or in the flow line VL.

[0065] Subsequently, a temperature lift AT is calculated using equation (1) as the difference between the second return temperature T2 and the first return temperature Tl. Using equations (2) and (3), a setpoint temperature T S0 n of the heating circuit medium can be calculated.

[0066] Since the losses and the total volume of heating circuit medium in the hydraulic circuit can change, the target temperature T S0 n is preferably determined again before each defrosting process or at the beginning of each loading process of the buffer storage 3. In particular, the heat losses of the hydraulic circuit can change, for example, depending on the outside temperature, so that the total thermal mass can also change.

[0067] The heating system 10 in Fig. 2 comprises the heat pump 1 itself as the sole heat generator. This means that the heat pump 1 generates the heat when the buffer tank 3 is being charged. During the defrosting process, however, the heat pump 1 is the load to which the heat from the buffer tank 3, or from the entire hydraulic circuit, is transferred. Thus, when the buffer tank 3 is being charged, the heat pump 1 initially generates the heat that is later used to defrost the heat pump 1.

[0068] In preferred embodiments, the heat pump 1 may have an additional auxiliary heat generator, for example an internal electric heating element (not shown), which may also be arranged in the outdoor unit ODU.

[0069] The process of loading the buffer tank 3 is completed when the measured return temperature is equal to or greater than the calculated target temperature T S0n. For safety reasons, a limit value can also be set that is 1 or 2 K above the set temperature T S0 n. As soon as the limit is reached, the defrosting process can begin.

[0070] Fig. 3 shows a second embodiment of a heating system 10 according to the invention. The heating system 10 of the second embodiment comprises, in addition to the heat pump 1, at least one second heat generator 12. The second heat generator 12 can, for example, be an external peak-load boiler operated with gas as fuel. Alternative examples of the second heat generator 12 include a gas condensing boiler, an oil boiler, a combined heat and power plant, a fuel cell, a solar thermal system, or other devices that can provide heat to the heating medium. The additional heat generator can also be referred to as an external heat generator since it is not an internal component of the heat pump.

[0071] According to a preferred embodiment, the second heat generator 12 can be an electrical heat generator, such as a heating element or the like. In preferred embodiments, two additional heat generators 12 can also be provided in the heating system 10.

[0072] The second heat generator 12 can be used when loading the buffer storage 3 to provide additional heat in the event that the heat pump 1 alone cannot provide sufficient heat to reach the specified target temperature T S0 n. During the defrosting process, the second heat generator 12 can thus support the loading of the buffer storage 3 with heat.

[0073] For example, if the limit or the target temperature T S0If n is not reached when charging the buffer storage tank 3, the second heat generator 12 can be activated to provide additional heat. The second heat generator 12 can be operated, for example, at a predetermined heating output, preferably at maximum heating output. According to a preferred embodiment, the heating output of the second heat generator 12 can be calculated or specified depending on a predetermined charging time of the buffer storage tank 3.

[0074] Preferably, the second heat generator 12 is operated with a minimum required heating output. To determine this heating output, a temperature gradient of the buffer storage tank 3 can be specified. The actual temperature gradient can be measured during loading of the buffer storage tank 3 and compared with the target gradient. If the measured gradient is lower than the specified gradient, the second heat generator 12 can be switched on accordingly. Reaching the limit value or the target temperature T S0 n can be checked, for example, after a specified period of time. Alternatively, the time required to reach the limit value or the target temperature T S0 The necessary heating output must be calculated in advance so that this heating output can be applied for a calculated period of time.

[0075] By integrating the heating power, the amount of heat Q introduced during the time interval Atzu The applied heating output dQzu / dt can, for example, be known as a default value of heat pump 1 and / or the second heat generator 12. In this case, knowledge of the fluid used as the heating circuit medium is not necessary.

[0076] Alternatively, the applied heating power dQ zu / dt can be calculated based on the mass of the heating circuit medium. For this, the thermodynamic properties, such as the density and heat capacity of the fluid used as the heating circuit medium, must be known. According to a preferred embodiment, water is used as the heating circuit medium. The heating power can then be expressed by the following formula: dQ Z u / dt = 8 (c - dm / dt - AT*) (4)

[0077] The mass flow dm / dt can be determined using a flow meter 13 located in the flow line upstream of the second heat generator 12. The temperature difference ΔT* is determined as the difference between the return flow temperature measured by the temperature sensor 11 and a temperature measured by a second temperature sensor 11 located upstream of the valve 4.

[0078] Using equation (4), the heat capacity c and the measured mass flow dm / dt as well as the measured temperature difference AT* and an empirically determined coefficient s can be used to calculate the heat output dQ introduced into the heating circuit medium. zu / dt based on the total thermal mass.

[0079] Fig. 4 shows a diagram describing the dependence of defrost energy on the outside temperature. The defrost energy is the amount of heat required to defrost the evaporator 5 and corresponds to the target heat quantity Q SOH. From Fig. 4, it can be seen that the defrost energy Qsoii required for defrosting increases as the outside temperature decreases. For example, at an outside temperature T1, the defrost energy Q1 required is higher than the defrost energy Q2 at an outside temperature T2 > T1.

[0080] Fig. 4 is merely an example of how the heat quantity can depend on the outside temperature. The heat quantity can also depend, for example, on the air humidity, the location of the ODU, the wind speed, etc. The functional relationship can therefore look different than that shown in Fig. 4 and, in particular, does not have to be a straight line.

[0081] In general, the target heat quantity Q S0 H depends on the type of heat pump 1. In particular, the defrost energy or target heat quantity Q S0H may depend on the dimensions of the components of the heat pump, in particular the evaporator 5, the heat exchanger 6 and / or the refrigerant circuit and the like. Furthermore, the target heat quantity Q so n depend on the heat capacity or the total thermal mass of the refrigerant or the refrigerant circuit.

[0082] The order of magnitude of the target heat quantity Q S0 H can, for example, be in the range of a few megajoules.

[0083] The features disclosed in the above description, the claims and the drawings may be important both individually and in any combination for the realization of the invention in its various forms.

Claims

PATENT CLAIMS 1. Method for operating a heating system (10) for heating and / or cooling a building with a heat pump (1) which heats a fluid heating circuit medium which circulates in a hydraulic circuit, wherein the circuit has a load (1), a buffer storage tank (3) and the heat pump (1) which are connected to each other via pipes, wherein the method comprises the following steps: Specifying a target heat quantity Q so ii in the hydraulic circuit; Recording an initial actual temperature TI of the heating circuit medium at a first time point tl; Recording a second actual temperature T2 of the heating circuit medium at a second time t2, which lies a predetermined period At after the first time tl; Determining a temperature rise AT as the difference between the second actual temperature T2 and the first actual temperature Tl; Measuring the amount of heat Q introduced into the hydraulic circuit by the heat pump (1) during the period At zu ; Determining a target temperature T S0 n of the heating circuit medium as a function of the target heat quantity Q S0 n, of the temperature difference AT and the amount of heat introduced Q zu ; and Operating the heat pump (1) depending on the determined target temperature T so ii.

2. Method according to claim 1, wherein the actual temperature of the heating circuit medium is measured between buffer storage (3) and load (1).

3. Method according to claim 1 or 2, wherein: the load is a refrigerant circuit of a heat pump (1); and the heating circuit medium flows through a heat exchanger (6) of the heat pump (1) to transfer heat to the refrigerant.

4. The method of claim 3, further comprising: Performing a charging process of the buffer storage tank (3) until the current actual temperature of the heating circuit medium is equal to or greater than the setpoint temperature Tsoii; and Performing a defrosting process to defrost an evaporator (5) of the heat pump (1).

5. Method according to claim 3 or 4, wherein the predetermined target heat quantity Q so ii is determined depending on an outside temperature and a device type of heat pump (1).

6. Method according to one of the preceding claims, wherein the heat pump (1) is operated at maximum heating power until the actual temperature of the heating circuit medium is equal to or greater than the setpoint temperature T. S0 n is.

7. The method of claim 6, further comprising: Determining the heating output required to reach the target temperature T soii to achieve; and if the required heating output is greater than the maximum heating output of the heat pump (1), operation of an additional heat generator (12) to heat the heating circuit medium.

8. A method according to any one of the preceding claims, further comprising: specifying a minimum temperature Tmin for the heating circuit medium; and determining the target temperature T. so ii of the heating circuit medium depending on the Minimum temperature Tmin.

9. Heating system (10) for heating and / or cooling a building, comprising: a hydraulic circuit with a load (1) and a buffer storage tank (3) connected to each other by pipes, wherein a fluid heating circuit medium circulates in the hydraulic circuit; a heat pump (1) arranged in the circuit, configured to heat the heating circuit medium; a temperature sensor (11) arranged in the hydraulic circuit, configured to detect an actual temperature of the heating circuit medium; and a control device for regulating and / or controlling the heat pump (1), wherein the control device is configured: a target heat quantity Q soii to specify in the hydraulic circuit; to record a first actual temperature TI of the heating circuit medium at a first time tl; to record a second actual temperature T2 of the heating circuit medium at a second time t2, which lies a specified period At after the first time tl; to determine a temperature difference AT as the difference between the second actual temperature T2 and the first actual temperature Tl; a quantity of heat Q introduced into the hydraulic circuit by the heat pump (1) during the period At zu to record; a target temperature T so ii of the heating circuit medium as a function of the target heat quantity Q S0 n, of the temperature difference AT and the amount of heat introduced Q zu to determine; and the heat pump (1) depending on the determined target temperature T S0 to operate.

10. Heating system (10) according to claim 9, wherein the temperature sensor (11) is arranged between the buffer storage tank (3) and the load (1).

11. Heating system (10) according to claim 9 or 10, wherein: the load is a refrigerant circuit of a heat pump (1) in the heating system (10); and the heating circuit medium flows through a heat exchanger (6) of the heat pump to transfer heat to the refrigerant.

12. Heating system (10) according to claim 11, wherein the control device is further configured to: perform a charging process of the buffer storage tank (3) until the current actual temperature of the heating circuit medium is equal to or greater than the setpoint temperature. Tsoii is; and to carry out a defrosting process to defrost an evaporator (5) of the heat pump (1).

13. Heating system (10) according to claim 11 or 12, further comprising an outdoor temperature sensor for measuring an outdoor temperature, wherein the control device is configured to provide the specified target heat quantity Q so ii depending on the outside temperature and a device type of heat pump (1).

14. Heating system (10) according to one of claims 9 to 13, wherein the control device is configured to operate the heat pump (1) at maximum heating power until the actual temperature of the heating circuit medium is equal to or greater than the setpoint temperature T S0 n is.

15. Heating system (10) according to claim 14, further comprising: an additional heat generator (12) for heating the heating circuit medium, wherein the control device is further configured to: determine a heating output required to maintain the setpoint temperature T so ii to achieve; and if the required heating output is greater than the maximum heating output of the heat pump (1), to operate the additional heat generator (12) to heat the heating circuit medium.

16. Heating system (10) according to any one of claims 9 to 15, wherein the control device is further configured to: specify a minimum temperature Tmin for the heating circuit medium; and the setpoint temperature T S0n of the heating circuit medium depending on the To determine the minimum temperature Tmin.

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